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Merge pull request #20925 from alexrp/windows-tls

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`std`: Some Windows TLS cleanup and fixes
This commit is contained in:
Andrew Kelley 2024-08-07 01:12:11 -07:00 committed by GitHub
commit 8184912a98
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GPG Key ID: B5690EEEBB952194
2 changed files with 17 additions and 15 deletions
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26
lib/std/start_windows_tls.zig → lib/std/os/windows/tls.zig
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@ -1,14 +1,15 @@
const std = @import("std"); const std = @import("std");
const builtin = @import("builtin"); const builtin = @import("builtin");
const windows = std.os.windows;
export var _tls_index: u32 = std.os.windows.TLS_OUT_OF_INDEXES; export var _tls_index: u32 = std.os.windows.TLS_OUT_OF_INDEXES;
export var _tls_start: u8 linksection(".tls") = 0; export var _tls_start: ?*anyopaque linksection(".tls") = null;
export var _tls_end: u8 linksection(".tls$ZZZ") = 0; export var _tls_end: ?*anyopaque linksection(".tls$ZZZ") = null;
export var __xl_a: std.os.windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLA") = null; export var __xl_a: windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLA") = null;
export var __xl_z: std.os.windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLZ") = null; export var __xl_z: windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLZ") = null;
comptime { comptime {
if (builtin.target.cpu.arch == .x86 and builtin.zig_backend != .stage2_c) { if (builtin.cpu.arch == .x86 and builtin.abi == .msvc and builtin.zig_backend != .stage2_c) {
// The __tls_array is the offset of the ThreadLocalStoragePointer field // The __tls_array is the offset of the ThreadLocalStoragePointer field
// in the TEB block whose base address held in the %fs segment. // in the TEB block whose base address held in the %fs segment.
asm ( asm (
@ -19,8 +20,6 @@ comptime {
} }
// TODO this is how I would like it to be expressed // TODO this is how I would like it to be expressed
// TODO also note, ReactOS has a +1 on StartAddressOfRawData and AddressOfCallBacks. Investigate
// why they do that.
//export const _tls_used linksection(".rdata$T") = std.os.windows.IMAGE_TLS_DIRECTORY { //export const _tls_used linksection(".rdata$T") = std.os.windows.IMAGE_TLS_DIRECTORY {
// .StartAddressOfRawData = @intFromPtr(&_tls_start), // .StartAddressOfRawData = @intFromPtr(&_tls_start),
// .EndAddressOfRawData = @intFromPtr(&_tls_end), // .EndAddressOfRawData = @intFromPtr(&_tls_end),
@ -31,10 +30,10 @@ comptime {
//}; //};
// This is the workaround because we can't do @intFromPtr at comptime like that. // This is the workaround because we can't do @intFromPtr at comptime like that.
pub const IMAGE_TLS_DIRECTORY = extern struct { pub const IMAGE_TLS_DIRECTORY = extern struct {
StartAddressOfRawData: *anyopaque, StartAddressOfRawData: *?*anyopaque,
EndAddressOfRawData: *anyopaque, EndAddressOfRawData: *?*anyopaque,
AddressOfIndex: *anyopaque, AddressOfIndex: *u32,
AddressOfCallBacks: *anyopaque, AddressOfCallBacks: [*:null]windows.PIMAGE_TLS_CALLBACK,
SizeOfZeroFill: u32, SizeOfZeroFill: u32,
Characteristics: u32, Characteristics: u32,
}; };
@ -42,7 +41,10 @@ export const _tls_used linksection(".rdata$T") = IMAGE_TLS_DIRECTORY{
.StartAddressOfRawData = &_tls_start, .StartAddressOfRawData = &_tls_start,
.EndAddressOfRawData = &_tls_end, .EndAddressOfRawData = &_tls_end,
.AddressOfIndex = &_tls_index, .AddressOfIndex = &_tls_index,
.AddressOfCallBacks = @as(*anyopaque, @ptrCast(&__xl_a)), // __xl_a is just a global variable containing a null pointer; the actual callbacks sit in
// between __xl_a and __xl_z. So we need to skip over __xl_a here. If there are no callbacks,
// this just means we point to __xl_z (the null terminator).
.AddressOfCallBacks = @as([*:null]windows.PIMAGE_TLS_CALLBACK, @ptrCast(&__xl_a)) + 1,
.SizeOfZeroFill = 0, .SizeOfZeroFill = 0,
.Characteristics = 0, .Characteristics = 0,
}; };

6
lib/std/start.zig
View File

@ -176,7 +176,7 @@ fn _DllMainCRTStartup(
lpReserved: std.os.windows.LPVOID, lpReserved: std.os.windows.LPVOID,
) callconv(std.os.windows.WINAPI) std.os.windows.BOOL { ) callconv(std.os.windows.WINAPI) std.os.windows.BOOL {
if (!builtin.single_threaded and !builtin.link_libc) { if (!builtin.single_threaded and !builtin.link_libc) {
_ = @import("start_windows_tls.zig"); _ = @import("os/windows/tls.zig");
} }
if (@hasDecl(root, "DllMain")) { if (@hasDecl(root, "DllMain")) {
@ -434,7 +434,7 @@ fn _start() callconv(.Naked) noreturn {
fn WinStartup() callconv(std.os.windows.WINAPI) noreturn { fn WinStartup() callconv(std.os.windows.WINAPI) noreturn {
@setAlignStack(16); @setAlignStack(16);
if (!builtin.single_threaded and !builtin.link_libc) { if (!builtin.single_threaded and !builtin.link_libc) {
_ = @import("start_windows_tls.zig"); _ = @import("os/windows/tls.zig");
} }
std.debug.maybeEnableSegfaultHandler(); std.debug.maybeEnableSegfaultHandler();
@ -445,7 +445,7 @@ fn WinStartup() callconv(std.os.windows.WINAPI) noreturn {
fn wWinMainCRTStartup() callconv(std.os.windows.WINAPI) noreturn { fn wWinMainCRTStartup() callconv(std.os.windows.WINAPI) noreturn {
@setAlignStack(16); @setAlignStack(16);
if (!builtin.single_threaded and !builtin.link_libc) { if (!builtin.single_threaded and !builtin.link_libc) {
_ = @import("start_windows_tls.zig"); _ = @import("os/windows/tls.zig");
} }
std.debug.maybeEnableSegfaultHandler(); std.debug.maybeEnableSegfaultHandler();